Gelling agents are conventionally used for the purposes of solidifying liquid substances, that is, gelatinously solidifying them, or increasing their viscosities, in various types of industrial fields (for example, coating, cosmetic, pharmaceutical and medical, spilled petroleum-treating, electronic and optical, and environmental fields).
These gelling agents include ones to gelatinize (solidify) water, and gelatinize (solidify) nonaqueous solvents, and solutions containing mainly the nonaqueous solvent, and the like. The structures of the gelling agents may be roughly classified into a high-molecular weight type and a low-molecular weight type. The high-molecular weight type gelling agents are used mainly for gelatinizing nonaqueous solvents, and have a feature that while a high-molecular weight polymer having lipophilicity takes oils in entangled molecules thereof and is swelled with the oils, the swelled polymer holds a solid state. By contrast, many of low-molecular weight type gelling agents contain hydrogen bonding functional groups (for example, an amino group, an amido group and a urethane group) in molecules thereof, and have a feature that water and nonaqueous solvents are gelatinized through hydrogen bonds (see, for example, Patent Literature 1). Low-molecular weight type gelling agents are common as gelling agents of water, but the development as gelling agents of nonaqueous solvents is relatively slow.
Additionally, although low-molecular weight type gelling agents having no hydrogen bonding groups are disclosed, for example, in Patent Literature 4 and Non Patent Literature 1, examples thereof are very few.
Further, Low molecular weight or high molecular weight organic gelling agents are used to solidify organic liquids. As described above, known low molecular weight gelling agents include a low molecular weight compound group which has a hydrogen-bondable functional group, such as an amino group, an amido group and a urea group, in their molecule. The low molecular weight gelling agents are suitable for use in the fields such as cosmetics, perfumery and sludge treatments.
On the other hand, polymeric gelling agents refer to a polymeric compound group having a three-dimensional network structure in their molecule. Well-known polymeric gelling agents include polyetheric compounds.
Many studies have been made on polymeric gelling agents, which have been applied in various fields.
As low molecular weight organic gelling agents are developed relatively later than high molecular weight ones, few types of the low molecular weight organic gelling agents are known. Known low molecular weight organic gelling agents include a dialkylurea derivative (Patent Literature 1) and perfluoroalkyl derivatives (Patent Literatures 2 and 3, and Non Patent Literature 1).